(188) Sensitization and decrease of conditioned pain modulation in patients with chronic low back pain

Abstract

Low back pain is an important public health issue that directly affects an individual’s quality of life and activities of daily living. Low back pain is also responsible for many absences from work and has high worldwide socioeconomic costs. Patients with chronic low back pain may present an increased widespread pain response, suggesting a central sensitization. Thus, the aim of this study was to assess the conditioned pain modulation and central sensitization in patients with chronic nonspecific low back pain. Sixty participants from both genders (30 healthy and 30 with chronic low back pain) where recruited. Pressure pain thresholds (PPTs) were recorded from lumbar area and from tibialis anterior (TA). Conditioned pain modulation was assessed using the cold pressor test. Patients with chronic nonspecific low back pain showed a smaller PPT in lumbar area (p=0.002) and in the TA (p=0.012) when compared to healthy subjects. Chronic low back pain patients also showed a dysfunction of endogenous pain modulatory mechanisms (p=0.001). These results suggest that patients with chronic low back pain present a local and segmental hyperalgesia. Moreover, the conditioned pain modulation is deficient in this population.